Pressure regulating device



y 26, 1956 A. 1.. THOMPSON PRESSUURE REGULATING DEVICE Filed Dec. 8, 1964 TO INLET MANIFOLD [N VENTOR. fifierf 6 73022 0502? BY 2 FROM clANKcAsE ATTORNEY toward the open position.

United States Patent 3,262,436 PRESSURE REGULATING DEVKCE Albert L. Thompson, Grand Blanc, Mich, assignor to General Motors Corporation, Detroit, Mich., a corporation of Delaware Filed Dec. 8, 1964, Ser. No. 416,705 4 Claims. (Cl. 123-119) This invention relates to pressure regulating devices for internal combustion engines and, more particularly, to pressure regulating devices adapted for connection between the crankcase and the induction system of an in ternal combustion engine to regulate the flow of crankcase vapors into the induction system.

It is well known in the art to ventilate the crankcase of an internal combustion engine by drawing vapors therefrom into some portion of the engine induction system. Commonly, in systems of this type, means are provided to admit fresh air into the engine crankcase to scaveng the crankcase vapors therefrom. In addition, it is usually desirable to provide some means of regulating the flow of the mixed crankcase vapors and fresh air from the crankcase to the induction system. As in the present invention, this may take the form of a pressure regulating device which senses the crankcase pressure and regulates the flow of vapors therefrom so as to limit the crankcase pressure to a predetermined desired value.

In a common application of such a regulator as dis closed herein, the crankcase vapors are drawn into the engine inlet manifold in which a varying degree of vacuum is present under normal engine operating conditions due to the restriction of the throttle valve located upstream of the inlet manifold. In such an application, the pressure regulating device is normally constructed to maintain a slight vacuum in the crankcase and is commonly referred to as a crankcase depression regulator.

The present invention relates primarily to crankcase depression regulators which include valve means biased In the embodiment shown herein, the valve means is spring biased and diaphragm means, responsive primarily to crankcase vacuum, are urged by atmospheric pressure against the valve means moving the valve means toward the closed position and regulating the flow of crankcase vapors through the crankcase depression regulator.

When using this type of regulator in an automotive engine, starting of the engine is made difficult by the fact that the valve means is normally open when the engine is stopped. As a result, a large flow of crankcase vapors is drawn into the intake manifold during starting which tends to dilute the combustible mixture supplied by the carburetor. In order to overcome this problem, the present invention provides overriding means to close the valve means when the engine is stopped and during engine starting when intake manifold vacuum is relatively low. These means take the form of an overriding spring combined with a restraining diaphragm. When the engine is stopped, the overriding spring forces the valve means closed. However, after starting of the engine, a sufficient buildup of manifold vacuum actuates the auxiliary diaphragm forcing the overriding spring to an inoperative position, thus allowing the regulating diaphragm and valve means to operate in the normal manner.

A feature of this invention is that it provides a crankcase pressure regulator including valve means biased in th opening direction and having overriding means for closing the valve means when the engine is stopped and during engine starting.

A further feature is that restraining means are provided for holding the overriding means in an inoperative position during normal engine operation.

Yet another feature of the invention is that the over- 3,252,436 Patented July 26, 1966 ice riding means comprise a coil spring within the regulator and movable into" operative engagement with the valve means.

Still another feature is that the restraining means include a diaphragm actuated by atmospheric pressure in response to the presence. of sufiicient vacuum in the induction system.

These and other novel features of the invention will be more apparent from the following specification and drawings in which:

FIGURE 1 is an elevational view of an internal combustion engine including a pressure regulator according to the invention; and

FIGURE 2 is a cross-sectional view of the pressure regulator shown in FIGURE 1.

Referring now to the drawings, numeral 10 generally indicates an internal combustion engine including a crankcase 12 which is closed by the usual oil pan 14 and communicates internally with rocker compartments closed by rocker covers 16 and 18. An oil filler cap 20 is provided on rocker cover 16 and may include air filtration media and an orifice through which a limited supply of ventilating air may be drawn into the engine crankcase. Engine 10 further includes an induction system comprising an air cleaner silencer 22 mounted upon the usual carburetor 24 having a throttle valve 26. Carburetor 24 is in turn carried by an inlet manifold 28 which distributes the combustible charge from the carburetor to the engine cylinders, not shown.

A crankcase ventilation system is provided for the engine including a pressure regulator generally indicated by numeral 30. This regulator is mounted on rocker cover 18 and connects with the interior thereof to draw crankcase vapors through the rocker compartment from the engine crankcase. A connecting tube 32 is provided connecting the pressure regulator to the inlet manifold 28 through which the crankcase vapors are drawn from the pressure regulator into the engine cylinders.

The construction of pressure regulator 30 is shown in FIGURE 2 to comprise a housing formed of a main body portion 36, an intermediate portion 38 and a cover portion 40.

Main body portion 36 includes an enlarged inlet portion 42 which is adapted to be received in a mounting device, not shown, forming a part of rocker cover 18. Extending upwardly from inlet portion 42, wall members 44 enclose a lower chamber 46 which communicates at all times with the engine crankcase. Centrally disposed within chamber 46 is a tubular means 48 terminating at its upper end in a valve seat 50 and including an internal passage 52 which connects with outlet passages 54, 56 and 58 extending through the main body, intermediate and cover portions, respectively. Passage 58 terminates within outlet connection means 60 provided in the cover portion for connection with tube 32.

Communication between chamber 46 and passage 52 is controlled by a frusto-conical valve member 62 which seats against valve seat 50 and includes a stem portion 64 extending downwardly through a guide opening 66 in the lower wall surrounding passage 54. A coil spring 68 extends between a spring seat 70 provided on tubular means 48 and an annular flange 72 around the top of valve 62 to bias the valve toward its open position.

In order to provide for regulating action of the valve, a flexible diaphragm 78 is mounted between body portion 36 and intermediate portion 38 closing the upper portion of chamber 46. Diaphragm 78 operatively engages valve 62 through a large disc member 80 located therebetween Diaphragm 78 and intermediate portion 38 partially define an intermediate chamber 82 which is open to atmospherh pressure through an orifice 84 provided in an outer wal of portion 38.

Cover portion 40 and intermediate portion 38 retain therebetween a second flexible diaphragm which closes the upper side of chamber 82 and defines with cover 40 an upper chamber 88. Chamber 88 connects with outlet passage 58 through an orifice 90 and is thereby always in communication with inlet manifold vacuum. Within chamber 88 and seated in an extending portion of cover 40 is a relatively heavy coil spring 94 which actuates diaphragm 86 through an intermediate disc member 96.

The operation of the above described regulator is as follows. With the engine operating normally, manifold vacuum in chamber 88 allows atmospheric pressure in chamber 82 to force diaphragm 86 upwardly compressing spring 94 to an inoperative position such as that shown in FIGURE 2. The normal leakage of blow-by gases into the engine crankcase tends to increase the crankcase pressure in chamber 46 allowing spring 68 to force valve 72 upwardly against the force of atmospheric pressure exerted downwardly on diaphragm 78. When valve 62 is open, manifold vacuum draws crankcase vapors from chamber 46 past valve seat 50 and through passages 52, 54, 56, 58 and connecting tube 32 into the inlet manifold 28. As this flow tends to exceed the volume of blow-by gases drawn into the crankcase and the volume of fresh air drawn into the crankcase through filler cap 20, the crankcase pressure is reduced, allowing atmospheric pressure on diaphragm 78 to move valve 62 toward the closed position. In this manner the flow is restricted, causing a balance between flow into and out of the engine crankcase and maintaining crankcase vacuum at a predetermined value.

When the engine is stopped, all chambers of the regulator return to atmospheric pressure, balancing pressures on the diaphragms. Spring 94 is thereby released from its compressed position and is allowed to force diaphragm 86 downwardly into engagement with diaphragm 78 and, since it is stronger than spring 68, it forces valve 62 into its closed position. When the engine is being started, the manifold vacuum is generally insufficient to lift diaphragm 86 against the force of spring 94 and, therefore, valve 62 remains in the closed position, preventing any excessive passage of crankcase vapors into the inlet manifold and consequent dilution of the fuel charge. Should engine starting vacuum be excessive in a particular application, the action of manifold vacuum on diaphragm 86 may be delayed by cont-rolling the size of orifice 90 so that the bleed down of pressure in chamber 88 is delayed past the time when engine starting normally occurs and thus the regulating valve 62 will remain closed during starting even though manifold vacuum builds up almost immediately.

After the engine is started, of course, chamber 88 reaches normal manifold vacuum and diaphragm 86 is forced upwardly compressing spring 94 to its operative position. As before mentioned, this allows normal regulating action of valve 62 to occur in response to pressures acting on diaphragm 78.

It should be understood that numerous changes might be made in the embodiment of the invention described within the scope of the instant invention which is intended to be limited only by the language of the following claims.

I claim:

1. For use in a crankcase ventilation system of an internal combustion engine of the type having a crankcase and an induction system:

actuating means operatively connected with the valve 15 means and responsive primarily to crankcase pressure to accomplish said flow regulation by movement of the valve means;

and supplementary means responsive to pressures in the engine induction system to close the valve means 2 during engine starting and to permit flow regulation during normal engine operation.

3. The device of claim 2 wherein said supplementary means includes overriding means operable to actuate the valve means in the closed position against the opening 25 bias and restraining means operatively connected with the overriding means and responsive to pressures in the engine induction system to restrain the overriding means from acting against and closing the valve means during normal engine operation.

4. A crankcase pressure regulator for use in connection with an engine including a crankcase and an induction system and adapted to be connected therebetween to regulate the flow of crankcase vapors from the crankcase to the induction system, said regulator comprising:

3 a housing having inlet and outlet means connectible with the crankcase and the induction system, respectively;

valve means in the housing and adapted to control the flow of fluids from the inlet to the outlet;

biasing means urging the valve means toward the open position;

actuating means engageable with the valve means to control the position of the valve means primarily in response to crankcase pressure;

supplementary biasing means operative to close the valve against the first mentioned biasing means; and

supplementary actuating means operatively engaging the supplementary biasing means and responsive to induction system vacuum to prevent the supplementary biasing means from closing the valve means whenever induction system vacuum is greater than a predetermined value;

whereby crankcase vapor flow regulation is permitted during normal engine operation while such flow is substantially cut oil under engine starting conditions.

References Cited by the Examiner UNITED STATES PATENTS 60 2,775,960 1/1957 Druzynski l231l9 2,833,303 5/1958 Leutwiler 137505.22 2,952,272 9/1960 Hansen 137-495 3,108,581 10/1963 Humphreys 1231 19 6 KARL I. ALBRECHT, Primary Examiner. 

1. FOR USE IN A CRANKCASE VENTILATION SYSTEM OF AN INTERNAL COMBUSTION ENGINE OF THE TYPE HAVING A CRANKCASE AND AN INDUCTION SYSTEM: VALVE MEANS NORMALLY OPERABLE TO REGULATE THE FLOW OF CRANKCASE VAPORS FROM THE CRANKCASE TO THE INDUCTION SYSTEM; AND SUPPLEMENTARY MEANS RESPONSIVE TO PRESSURES IN THE ENGINE INDUCTION SYSTEM TO CLOSE THE VALVE MEANS DURING ENGINE STARTING AND TO PERMIT SAID FLOW REGULATION DURING NORMAL ENGINE OPERATION. 